MMSE linear interference cancellation for GEO land mobile satellite systems

We consider a general model for a multiple access asynchronous Gaussian slowly time-varying channel with multiple observations, as obtained from an antenna array. We derive analytical expressions for the output MSE of several linear multiuser receivers. We focus on a fractionally-spaced linear receiver which is robust to timing and waveform mismatch and lends itself to adaptive implementation and we evaluate its bit error rate in the uncoded case. Numerical examples are based on a narrowband channel with FDMA/TDMA access typical of the uplink of a geostationary Earth orbit (GEO) satellite system for land mobile communications.